Heat exchange unit



April 25, 1939.

c. A. LEIDIG .2,155,666`

HEAT EXCHANGE UNIT Filed DSC. 4, 1936 Fi. i.

INVENTOR Patented Apr. 25, 1939 HEAT EXCHANGE UNIT Clarence A. Leidig, Buffalo, N. Y., assigner of forty-five per cent to Silas C'. Wead, North Tonawanda, N. Y.

Application December 4, 1936, Serial No. 114,218

7 Claims.

This invention relates to a new .and improved heat exchange unit and particularly to a .device for elevating the temperatures-of liquids by Ymeans of a current of lhot gas, but `which is susceptible of other uses, as for instance, by placing the unit in a surrounding medium-of low temperature Vand passing through the unit a liquid which is to be cooled.

It is an object of the present invention to provide a device which may be arranged within small compass, as for instance in a conduit for hot gases, and one which will .offer .a minimum of resistance vto the normal iiow .of .gas in the conduit and at the same time will take a comparatively large proportion of the heat from the gas and transfer it to the duid passing through the heat exchange unit.

I n one application ci my invention the .heat transfer unit which forms the sub-ject .matter of the present invention is disposed in the Vexhaust conduit of an internal combustion engine.

The internal combustion engine may be the propelling means for an `aeroplane and the heat taken from the exhaustgases by use of the present invention may be used for heating the cockpit.

In installations of this class thermal efficiency, minimum resistance to lthe free passage of the exhaustgas in the conduit, and compactness and light weight are extremely important considerations. My invention affords a device which meets these requirements and which is of simple construction. Oi course, the particular desirability of my device in the instance suggested does not render it less lit for use in other cases where an efcient, compact heat and exchange unit is required.

In the accompanying drawing, I have illustrated the embodiment of .my invention which I at present prefer but it is to be understood that the form there disclosed is merely exemplary and that many modiiications might be made Without departing from the spirit or scope of the invention as deined in the appended claims.

Inthe drawing Fig. 1 illustrates one form .of my present invention in side elevation and disposed in a hot gas conduit. Parts of the'heat transfer unit have been broken away to better illustrate the interior construction;

Fig. 2 is a cross sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is a partial cross sectional view taken on line 3---3` of Fig. 1;

Fig. 4 is a view similar to Fig. 2 showing amodifled form vof my invention.

.In.Fig. l of .the drawing Ill designates the coniining chamber for the medium which is to give oli :or 4take on heat to effect a change in temperature of the fluid passing through the unit. In the .present .instance this coniining chamber .is t5 the vexhaust conduit of the internal combustion engine of an aeroplane and one form of my present invention is shown disposed therein. The form illustrated in Figs. 1, 2 and 3 includes a series of iiattenedtubes II, I2 `and I3. While in the form illustrated these tubes are three in number. it will be understod that any suitable number of similar tubes may be added to the series.

Disposed within the tubes l I, I2 and I3 are similar but smaller flattened tubes Ill, I5 and 6 which Aare supported centrally of the tubes II, I2 Yand i3., respectively, by spacing blocks I6 disposed adjacent the ends of the tubes and welded thereto. Each pair of inner and outer tube members `defines an elongated iiuid passage or chamber of annularcross section.

The .several tubes il, I2 and I3 are joined to each other and maintained in spaced parallel relation with their iiat side portions facing each other by blocks il and I8 which are `disposed between -each pair of tubes at their opposite ends and welded thereto.

End plates 2l and 22 are provided whose clr cumferential coniigurations coincide with the outline of th-e ends of the assembled group oi tubes II, I2 and I3. Openings 23 are provided in the end plates 2I and 22 and these openings are of the same contour as the interior of each of the smaller flattened tubes Ill, I5 and I6.

A suitable number of tie bolts 24 are preferably provided, each of which extends through both end plates 2| and 22 at such points that the intermediate portion of each tie bolt passes through the space between the outer and inner flat tubes at their end portions at which points the annular space is of greater width than at the flat side portions.

.The lowermost tube I3 of the series is provided -adjacent one of its -ends with an inlet pipe 26 and from the upper surface of the tube II there extends an outlet pipe 21 which is disposed at the opposite end of the device from the pipe 2B when, as in the present instance, the number of tubes is odd, but is disposed at the same end of Athe device as pipe 26 when an even number of tubes are used.

When the tubes and end plates are assembled a plurality of closed annular compartments or passages are provided between each pair of outer 55 and inner :attened tube members. These compartments are interconnected in a manner which will now be described. The bottom portion of the tubular member Il is notched at the end opposite the outlet pipe 21 and the block I1 lying immediately between the tube I I at this point and the top of the tube I2 is similarly notched to form the passageway 28 which appears in Fig. 3. The tubes I2 and I3 are in like manner provided with a similar passageway 29 extending between them and lying at the opposite end of the device from the passage 28.

When the device is installed for use the pipes 26 and 21 are connected in a normally closed fluid circuit (not shown) and the heat of the exhaust gases emitted by the internal combustion engine passes through the conduit I9 and surrounds the outer surfaces of all of the tubes II, I2 and I3 and the inner surfaces of the tubes I4, I5 and I6. 'Ihis construction I have found to give highly efficient results, having in mind the most satisfactory balance or proportion between area of radiation, freedom of ow of the hot gas and the uid to be heated, and at the same time giving consideration to the requirements of sturdiness and economy of manufacture. In this way heat is transferred from the exhaust gas of the engine to the water or other fluid which occupies the annular spaces between the tubes II, I2 and I3 of the tubes I4, I5 and I3 respectively causing the heated uid to rise and emerge through the pipe 21 and additional supplies of cool fluid to enter the heat exchanger through the pipe 26.

It will be seen that owing to the disposition o-f the interconnecting passages 28 and 29 at alternate ends of the device the iluid is caused to take a circuitous path which completely traverses the annular spaces between each of the tubes from the pipe 26 to the outlet 21. The fluid passes from left to right, as seen in Fig. 1, through the space between the tubes I3 and I6, through the passage 29 and then from right to left in the space between the tubes I2 and I5, then through the passage 2S and from left to right through the space between the tubes II and I4 and out of the outlet pipe 21.

A modification of the form of invention illustrated in Figs. 1, 2 and 3 is shown in Fig. 4 wherein the spacing blocks I1 and I8 are omitted and the outer tubes II, I2 and I3 are secured directly to each other as by welding or the like. The device illustrated in Fig. 4 is in all other respects substantially the same in construction and operation as the device illustrated in Figs. 1, 2 and 3. In the device of Fig. 4 a part of the radiating surface is sacrificed to secure greater compactness of construction.

What is claimed is:

l. A heat exchange unit comprising a series of tubular members arranged in parallel relationship, a second series of tubular members of smaller cross-sectional area than said flrst'series, one each of said second series of tubular members being arranged centrally within each of said first series of tubular members to provide annular fluid chambers therebetween, said inner and outer tubular members being of substantially the same length, a closure member at each end of said tubular members having a at face disposed against the ends of the several members for closing off said annular spaces and having apertures therein communicating with the interiors of the tubular members of said second series whereby the outer surfaces of said rst series of tubular members and the inner surfaces of said second series of tubular members are utilized in radiating heat, passages for establishing communication between adjacent annular chambers, said passages being disposed alternately at opposite ends of said tubular members, and an inlet port for communicating with the annular chamber at one end of said series of tubular members and an outlet port communicating with the annular chamber at the opposite end of said series of tubular members.

2. A heat exchange unit comprising a series of tubular members arranged in parallel relationship, a second series of tubular members of smaller cross-sectional area than said rst series, one each of said second series of tubular members being arranged centrally within each of said rst series of tubular members to provide annular fluid chambers therebetween, said inner and outer tubular members being of substantially the same length, a closure member at each end of said tubular members having a fiat face disposed against the ends of the several tubular members for closing olf said annular spaces and having apertures therein communicating with the interiors of the tubular members of said second series whereby the outer surfaces of said rst series of tubular members and the inner surfaces of said second series of tubular members are utilized in radiating heat, passages for establishing communication between adjacent annular chambers, said passages being disposed alternately at opposite ends of said tubular members, an inlet port for communicating with the annular chamber at one end of said series of tubular members and an outlet port communicating with the annular chamber at the opposite end of said series of tubular members, and tie rods extending between said end closure members and engaging therewith to retain said closure plates in a fluid-tight manner against the ends of said tubular members in assembled relation.

3. A heat exchange unit comprising a series of tubular members arranged in parallel relationship, a second series of tubular members of smaller cross-sectional area than said first series, one each of said second series of tubular members being arranged centrally within each of said first series of tubular members to provide annular fluid chambers therebetween, said inner and outer tubular members being of substantially the same length, a closure member at each end of said tubular members having a at face disposed against the ends of the several tubular members for closing off said annular spaces and having apertures therein communicating with the interiors of the tubular members of said second series whereby the outer surfaces of said first series of tubular members and the inner surfaces of said second series of tubular members are utilized in radiating heat, passages for establishing communication between adjacent annular chambers, said passages being disposed alternately at opposite ends of said tubular members, an inlet port for communicating with the annular chamber at one end of said series of tubular members and an outlet port communicating with the annular chamber at the opposite end of said series of tubular members, and tie rods extending between said end closure members and engaging therewith to retain said closure plates in a fluid-tight manner against the ends of said tubular members in assembled relation, the intermediate portions of said tie rods being disposed within said` annular fluid chambers.

4. A heat exchange unit comprising a series of tubular members of elongated cross-section arranged in parallel relationship along an axis coincident with their shorter cross-sectional extent, a second series of tubular members of substantial similar cross-section as the tubular members of said first series but of smaller cross'- sectional area than said first series, o-ne each oi said second series of tubular members being arranged centrally within each of said rst series of tubular members to provide iluid chambers extending continuously about the smaller tubular members, said inner and outer tubular members being of substantially the same length, a closure member at each end of said tubular members having a flat face disposed against the ends of the several tubular members for closing off said fluid chambers and having apertures therein communicating with the interiors of the tubular members of said second series whereby the outer surfaces of said iirst series of tubular members and the inner surfaces of said second series of tubular members are utilized in radiating heat, passages for establishing communication between adjacent annular chambers, said passages being disposed alternately at opposite ends of said tubular members, and an inlet port for communieating with the annular chamber at one end of said series of tubular members and an outlet port communicating with the annular chamber at thev opposite end of said series of tubular members.

5. A heat exchange unit comprising a series of tubular members of elongated cross-section arranged in parallel relationship along an axis coincident with their shorter cross-sectional extent, a second series of tubular members' of substantially similar cross-section as the tubular members of said rst series but of smaller crosssectional area than said rst series, one each of said second series of tubular members being arranged centrally Within each of said first series of tubular members to provide fluid chambers extending continuously about the smaller tubular members, said inner and outer tubular members being of substantially the same length, a closure member at each end of said tubular members having a flat face disposed against the ends of the several tubular members for closing 01T said fluid chambers and having apertures therein communicating with the interiors of the tubular members of said second series whereby the outer surfaces of said iirst series of tubular members and the inner surfaces of said second series of tubular members are utilized in radiating heat, passages for establishing communication between adjacent annular chambers, said passages being disposed alternately at opposite ends of said tubular members, an inlet port for communicating with the annular chamber at one end of said series of tubular members and an outlet port communicating with the annular chamber at the opposite end of said series of tubular members, and tie rods disposed in said uid chambers and engaging at their opposite ends with the end closure members to retain said closure members in a fluid-tight manner against the ends of said tubular members in assembled relation.

6. A heat exchange unit comprising a series of tubular members arranged in spaced parallel relationship, a second series of tubular members of smaller cross-sectional area than said first series, one each of said second series of tubular members being arranged centrally Within each of said first series of tubular members to provide annular fluid chambers therebetween, said inner and outer tubular members being of substantially the same length, a closure member at each end of said tubular members having a flat face disposed against the ends of the several members for closing oi said annular spaces and having apertures therein communicating with the interiors of the tubular members of said second series whereby the entire outer surfaces of said first series of tubular members and the inner surfaces o-f said second series of tubular members are utilized in radiating heat, passages for establishing communication between adjacent annular chambers, said passages being disposed alternately at opposite ends of said tubular members, and an inlet port for communicating with` the annular chambers at one end of said series of tubular members, and an outlet port communicating with the annular chamber at the opposite end of said series of tubular members.

7. A heat exchange unit comprising a series of tubular members of elongated cro-ss-section arranged in parallel relationship along an axis co-incident With their shorter cross-sectional extent and with their elongated side wall portions in abutting relation, a second series of tubular members of smaller cross-sectional area than said rst series, one each of said second series of tubular members being arranged centrally within each of said rst series of tubular members to provide annular fluid chambers therebetween, said inner and outer tubular members being of substantially the same length, a closure member at each end of said tubularr members having a at face disposed against the ends of the several members for closing off said annular spaces and having apertures therein communicating with the interiors of the tubular members of said second series whereby the outer surfaces of said rst series of tubular members and the inner surfaces of said second series of tubular members are utilized in radiating heat, passages for establishing communication between adjacent annular chambers, said passages being disposed alternately at opposite ends of said tubular members, and an inlet port for commuicating with the annular chamber at one end of said series of tubular members and an outlet port co-mmunicating with the annular chamber at the opposite end of said series of tubular members.

CLARENCE A. LEIDIG. 

